• family caregiver;
  • cancer;
  • oncology;
  • experiences;
  • caregiver burden;
  • problems


  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

Objective: To adequately help family caregivers (FCs) of cancer patients, clinicians need to understand the complexity of the problems and responsibilities associated with cancer patients illness that FCs experience.

Methods: This systematic review identified the types of problems and burdens that FCs of cancer patients experience during the patient's illness. We also analyzed the language caregivers use to communicate their problems and responsibilities related to caregiving for the cancer patient.

Results: Of 2845 titles identified, 192 articles met the inclusion criteria and are included in this review. Of these, 164 were research-based. In addition to FC responsibilities and the impact of being a caregiver on daily life, a number of other physical, social, and emotional problems related to caregiving for these FCs were identified.

Conclusion: A substantial evidence base supports the conclusion that FCs experience many difficult problems and increased responsibilities during and after the patient is undergoing treatment and rehabilitation for cancer. The insights gained from this review will help researchers and clinicians to understand the complexity of problems and responsibilities FCs experience. This understanding may encourage them to include support for FCs as part of total or holistic patient care. However, more research is needed to better understand the variations in caregiving experiences over time; how the caregiving perspective is influenced by different cultural, ethnic, or socioeconomic backgrounds as well as gender and age; and how problems and responsibilities related to caregiving interfere with daily life. Copyright © 2009 John Wiley & Sons, Ltd.


  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

A cancer diagnosis has a significant impact not only on the patients, but also on their family members. Family caregivers (FCs) are often the primary source of social and emotional support for patients and play a major role in how well patients manage their illness 1–3. Given the trend toward shorter hospital stays, patients are increasingly left to self-manage their illness, including the often debilitating side effects of treatment at home. Consequently, the burden of responsibility for FCs of cancer patients has increased, making their role in supporting the patient even more important. In this review, a FC is defined as ‘who the patient says it is’ 4. Therefore, FCs can include a whole range of relationships, such as blood relatives, friends, neighbors, or others 5. FCs are a valuable source of essential and unpaid support, serving as a critical supplement to other formal health care services 6, 7.

Given the crucial role they play in patient recovery and illness management, FCs should be included in patient care from a family-as-patient perspective. FCs are important to clinical outcomes. Therefore, supporting FCs indirectly supports patients as well. The question is how best to support FCs. FCs experience many problems and burdens related to caregiving.

Psychosocial and educational interventions tailored exclusively for FCs can strengthen the FCs' ability to manage living with the cancer patient, reducing the attendant distress, anxiety, and depression 1, 2, 8–10.

Another potential powerful intervention to support FCs is Internet support. To help meet the FCs' need for support and information, our research team wants to develop an Internet-based support system for FCs, building on the work we have done creating an Internet-based support system for cancer patients 11.

This support intervention is designed to assist FCs to manage their own health problems and cope with the burdens of caring for a cancer patient by providing tailored information for FCs, as well as a venue for peer and professional communication and support. To develop and test this support system, we performed a review of the literature to identify the breadth and depth of problems faced by FCs of cancer patients. In addition, we examined the language they use to communicate their problems to gain a better understanding of their perspectives and to tailor the intervention to their language.

Although a few earlier reviews provided some insight into FCs of cancer patients' problems, including physical and emotional symptoms, these reviews were not exhaustive; and they included only certain problems or aspects of the FC experience 12–23. To date, no known review has addressed the full scope of problems faced by FCs of cancer patients nor included their perspective. Therefore, insights gained from our review will not only contribute to better support tools, but also help researchers and clinicians to identify caregivers who are struggling with negative or difficult experiences in relations to patient care, and better understand the FCs' problems and perspectives in order to improve communication with and better tailor information and support for these FCs 5, 24. Therefore, in this review, we have primarily focused on the burdensome experience of caregiving, although we are well aware of the criticism of conceptualizing caregiving only as a burdensome experience on the grounds that caregiving can also be rewarding 5, 25.

Therefore, the purpose of this review was to summarize the state of knowledge on the following questions:

  • 1
    What physical and psychosocial health problems do FCs of cancer patient's experience, as reported in the literature? Similarly, what burdens do they carry due to their caregiving responsibilities?
  • 2
    How do FCs describe their problems and responsibilities?


  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

Search strategy and data sources

For this review, we conducted a systematic search of the following electronic databases: MEDLINE (1950–February 2008), CINAHL (1982–February 2008), EMBASE (1980–February 2008), PsychINFO (1985–February 2008), AMED (1985–February 2008), ISI (1990–February 2008), and Cochrane Library (2008). In each database, we searched for every term listed below in the database thesaurus and used the free text/key word method. We also searched for synonyms and modified versions of these terms to best utilize each database/thesaurus:

  • Caregiver*, next of kin*, significant other*, carer*

  • Cancer*, neoplasm*, oncology*

  • Symptom*, burden*, problem*, consequence*, sequela*, side effect*, adverse effect*, untoward effect*

  • Quality of life* (QoL), Health related quality of life* (HRQoL)

  • Information*, need*

  • Relationship*, sexual*

Inclusion criteria were English- and Scandinavian-language articles that discussed FCs of cancer patients where both FCs and patients were older than 18 years of age, regardless of research design. All types of self-reported problems and burdens related to caregiving responsibilities (physical, social, emotional, impact on daily life) were reviewed. We excluded articles that discussed the perspective of cancer patients or professional caregivers.

Data abstraction

The search of the online databases yielded 2845 titles. We excluded 2596 after reading the abstract because they did not meet the inclusion criteria. Of those remaining, 248 were retrieved in full text; we excluded 56 of this subset after reading the articles because they did not meet the inclusion criteria. In summary, we retained 192 articles for this review.

Inclusion and exclusion criteria were assessed by an independent second reviewer on 10% of the total articles. Agreement between two reviewers was greater than 90%, with consensus reached on whether the articles met the inclusion or exclusion criteria. For the articles on which the reviewers disagreed, a second review was undertaken until consensus was reached.


  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

Types of studies

A total of 192 articles described various problems and burdens related to cancer patient caregiving responsibilities. Of the 192 studies, 164 articles were research-based studies, 12 were systematic reviews 12–23, 6 were more general reviews, and 10 were expert opinions 6, 26–40. Of the research-based studies, 112 used quantitative methods with experimental, quasi-experimental, or descriptive designs, 35 studies used qualitative methods, and 17 studies used mixed methods. Quantitative approaches relied heavily on questionnaires or surveys that evaluated physical, social, and psychological domains. Qualitative methods included individual interviews and focus groups.

Caregiver characteristics

A total of 19 466 adult FCs of cancer patients participated in the reviewed research-based studies (not including 2/164 [1.2%] of the research-based studies that did not report the exact number of FCs). Of the total number of FCs, 10 222 (63.5%) were women and 5871 (36.5%) were men. FC gender was not reported in 12/163 (7.3%) studies, representing a total of 3373 (17.3%) FCs of unknown gender. Mean age of the FCs was 54.1 years. Eight studies (4.8%) did not report FC age. The most common forms of cancer, included in the studies, were breast, prostate, gastrointestinal, colon, and lung. Most of the FC studies included patients with multiple cancer diagnoses. The type(s) of cancer was not reported in 37/164 (22.5%) of the research-based studies.

Most of the research-based studies were carried out in the United States (94/164 [57.3%]); 29/164 (17.6%) studies in Europe, 16/164 (9.8%) in Asia, 14/164 (8.5%) in Australia, 8/164 (4.8%) in Canada, and 3/164 (1.8%) in Africa. Other FC data reported included education (113/164 or 68.9%), employment status (85/164 or 51.8%), and FC income (52/164 or 31.7%). It was difficult to estimate a family's overall socioeconomic status because it was measured in different ways by the studies. The relationship of the FC to the patient was most frequently spouse/partner, adult child (mostly daughters), parent, sibling, son/daughter-in-law, grandchild, niece, or friend. Most of the studies had samples consisting of different types of relationships between patient and FC. The largest sample was 1700 41, the smallest was 5 42. Race or ethnicity were reported by 83/164 (50.6%) studies.

Types of problems

We identified more than 200 problems and burdens related to caregiving responsibilities in the literature. The specific problems are categorized in Tables 2–5. The most frequently studied categories were social and emotional. The problem lists show that FCs experience emotional problems, like anxiety, depression, fatigue, and sleep problems, which also have physical elements. For the purpose of this study, anxiety and depression were categorized as emotional problems and fatigue and sleep problems as physical health problems in the problem list.

Table 1. Number and references of types of problems and responsibilities experienced by family caregivers of cancer patients
Problems and responsibilitiesNumber and references
Physical, social, or emotional problems and responsibilities in combination97 3, 8, 9, 25, 42–45, 47, 49, 50, 52, 53, 55, 56, 58–60, 68, 74, 75, 81, 82, 85, 87, 89–157
Social problems and need for information29 10, 41, 51, 61–63, 66, 67, 69, 86, 88, 119, 158–174
Responsibilities and impact on daily life20 64, 65, 76–80, 175–187
Emotional problems11 71, 72, 188–196
Physical health problems and quality of life7 46, 48, 197–201
Table 2. Physical health problems reported by family caregivers of cancer patients
Back pain
Leg pain
Muscle tension
Sleep problems
Disturbed sleep
Poor sleep quality
Reduced sleep time
Restless sleep
Loss of energy
Physically exhausted
Other health problems
Loss of appetite
Loss of physical strength
Loss of weight
Table 3. Social problems and need for information reported by family caregivers of cancer patients
Financial difficulties
Difficult to pay bills
Lack of sick leave
Lack of vacation time
Loss of income
Loss of savings
Altered educational plans
Change in employment status
Engage in fewer work activities
Given up work
Hard to concentrate on work
Job interruptions
Less effective overall at work
Long service leave
Missed work
Reduced work hours
Stop work to care
Work adjustment
Role strain
Balancing multiple roles
Changes in duty expectations
Changes in responsibilities
Difficult to manage many life roles
Less marital satisfaction
Pulled many ways at once
Role changes
Role conflict among family members
Spousal role problems
Loss of intimacy
Loss of togetherness
Relational deprivation
Managing the environment
Difficult to communicate with staff
Difficult to coordinate the care of different professionals
Difficult to deal with others' emotional responses
Difficult to get a second opinion from another doctor
Difficult to get help
Feeling of being unappreciated
Struggling with health care system
Telling others that the cancer had a cost
Frustrated when information was not given
Information needed about:
 Cause of cancer
 Clinical trials
 Community services
 Disease process
 Drugs available
 Expectations for the future
 Expected physical problems
 How to provide physical care
 Natural therapies
 Possibilities for treatment
 Referrals for second opinion
 Side effects
 Specific cancer sites
 Support groups
 Symptom management
 Where to get help when needed
Information important to make sense of the illness
Information when needed to have choices
Lack of communication with health care professionals
Lack of information
Table 4. Emotional problems and reactions reported by family caregivers of cancer patients
Anxiety for own health
Not wanting to leave the patient alone
Fear of an unpredictable future
Fear of genetic risk
Fear of losing the patient
Fear of recurrence/metastasis of cancer
Fear of second cancer
Fears about the cancer spreading
Fears about the patient's physical disability or deterioration
Frightened by the changes
Live in constant fear
Scared about surgery and risks
Dealing with unpredictability of the future
Always up and down
Being on an emotional roller coaster
Easily irritated
Feel bad
Feel abandoned
Feel afraid
Feel bored or useless
Feel upset
Feelings of inadequacy (wish to do more)
Sad feelings
Positive emotional experiences from caregiving
Appreciate the time together
Awakening of own strengths
Brought the whole family closer
Chance to ‘pay back’
Chance to provide care
Change of worldview
Treasure their lives
Greater sense of connectedness
Enjoy caring
Feel good inside
Feel very good about doing it
Feeling good about the role
Finding purpose and meaning
Increased respect of each other
Moral duty
More intimacy
Quality time
Self-esteem (positive)
Strengthened relationship
Taught us much
Challenging emotional reactions to caring
Accepting the disease
Contemplating suicide
Dealing with unfamiliar situations
Dealing with feelings of separation and loss
Difficulty in seeing any positive aspects of the situation
Difficulty in showing emotions
Emotionally drained
Emotionally exhausted
Extreme mental exhaustion
Feel alone in decisions
Feeling excluded from the focus of care
Feel underprepared for tasks
Keepers of secrets (info, prognosis, finances)
Lack of concentration/memory
Loss of control
Managing emotional tensions
Managing one's own feelings
Struggle to balance the emotions
Under considerable pressure
Sexual issues
Change in sexual function
Dealing with side effects:
 Urinary problems
Dissatisfaction with sexual relationship
Lack of communication about sexual concerns
Libido loss
Marital relationship (negative)
Regret and feelings of loss connectedness
Loss of intimacy
Dealing with patient's erectile dysfunction
Wish more help with sexual changes
Wish to be asked about sexual concerns
Worries about fertility
Table 5. Burden related to responsibilities and impact on daily life
Direct care for patient
Assisting with mobility
Behavioral management
Change diapers
Change dressing
Emotional support
Give baths
Give massage and exercise (physically and mentally)
Help the patient to deal with anxiety and depression
Help the patient to deal/manage with mood/behavior changes
Manage patient's feelings
Managing patient's symptoms (fatigue, poor appetite, coordination problems, frequent urination, trouble sleeping, weight loss, difficulty breathing, diarrhea, etc.)
Monitor patient's symptoms
Obtaining medications
Shave the patient
Indirect care for the patient
Accompanying patient to appointments
Another pair of ears
Asking for help
Assisting with communication
Assisting with medical bills and finances
Dealing with medications–stressful
Difficult to understand the patient's health status and treatment regime
Filling out forms
Finding care while away
Help the patient to fill the days
Household tasks/management (running errands, lawn care, laundry, gardening, walking dogs, entertaining visitors)
Make decisions
Monitor the activities of the patient
Observe for side effects
Provide care and support
Provide medical/nursing treatments
Report symptoms/progress
Schedule and coordinate appointments
Standing by
Translator of the process for other family members
Other care responsibilities
Child care
Continuity and security for the children
Deal with other family responsibilities
Difficult to continue doing the things I do for others
Increasing care for others
Impact on caregiver's daily life
Activities centered on care
Activity restriction
Cannot practice hobbies
Changed relationship with friends and social network
Changes in usual routine and lifestyle
Disrupted schedule
Eliminated things from schedule
Leisure activity deficit
Limited ability to participate in valued activities and interests
Loss of contact with other individuals
Loss of independence
Loss of joy and restricted freedom
Loss of personal time and pleasure
Loss of planned activities
Organizing new living arrangements for the family
Reduced contact with children or other family members
Restricted social life
Try to maximize the sense of life carrying on as normal
Visit family/friends less

As described in Table 1, of the 164 research-based studies, 97 described the physical, social, and/or emotional problems, and the burdens related to caregiving in combination. Twenty-nine studies described social problems and the FCs' need for information (e.g. financial difficulties, problems with work or education, role strain, isolation, trouble managing the environment, and the need for information). Twenty studies described FCs' responsibilities (e.g. direct and indirect care, other care responsibilities, and impact on daily life). Eleven studies described emotional problems and reactions (e.g. anxiety, depression, fear, uncertainty, feelings of powerlessness, mood disturbances, positive and challenging responses to caring, and sexual issues). Five studies described FCs' quality of life and two studies described only physical problems (e.g. fatigue, sleep disturbance, pain, and other health problems).

Physical health problems experienced by FCs

A number of studies have shown that FCs of cancer patients experience different physical health problems as a consequence of their role. The most prevalent problems included sleep disturbance, fatigue, pain, loss of physical strength, loss of appetite, and weight loss 43–48.

Social problems and the need for information

Several studies reported that FCs experience social problems or challenges associated with role strain, finances, employment/education, isolation, and managing the environment 45, 49. When a family member is suffering from cancer, roles change. Family members experience changes in expectations and responsibilities, as well as intrafamilial relationships 50. The burden on FCs frequently increases. This especially applies to caregivers who, in addition to caring for the person with cancer, also care for children or aging parents. These FCs often feel stretched in many directions at once. They worry about the patient when they are not with him or her, and they worry about their other family members when they are with the patient. As a result, they try to do it all—at work, at home, and with the patient 49. FCs report that they feel inadequate when they fail to meet the high standards they set for themselves. Those who did not have flexible jobs or employers often take sick leave and vacation. These FCs worried about economics 51. Although some felt their work provided a means to relax, others found it difficult to concentrate on their professional tasks. Caregivers often reported feelings of isolation 52–55. Some reported that the work of caregiving itself disrupted their ability to socially engage with others 56, 57; because their focus was on the patient, their own needs were neglected 58, 59. In two studies, FCs without family or nearby friends experienced considerable loneliness 58, 59.

Information was one of the most important support needs for FCs of cancer patients 60–65. FCs felt they were responsible for gathering information about the disease 61, and described becoming researchers, emphasizing the benefits of and necessity for being informed caregivers 66. FCs reported a need for more information about diagnosis, treatments, and management of symptoms, side effects, and physical care, particularly regarding home care after discharge 60, 67, 68. Often the FCs described not knowing what their information needs were until a crisis occurred. When information was not provided by the clinicians, FCs felt frustrated and helpless 65.

FCs want detailed and specific information tailored to their unique situations as FCs, and to their social and emotional needs at different stages of their cancer care journey, as well as to the physical care needs of their patients 62, 65, 69, 70. Information was needed in order to be prepared for caring 65. FCs preferred face-to-face communication with clinicians 61. The FCs found other sources of information, including written material (e.g. pamphlets and books; other health professionals, such as social workers and pharmacists), the Internet, and networking with other families, neighbors, and clinical staff. Frequently, FCs sought someone they could contact for advice at the time when this was most needed 65.

Emotional problems and reactions

Several studies have found that FCs experience more depression and anxiety than non-caregivers. They also experience different difficult emotional reactions to caring, such as feelings of fear, uncertainty, hopelessness, powerlessness, and mood disturbances 71–73. Several studies have reported the emotional reactions FCs experience in relation to caregiving, both challenging and positive experiences 58, 74. Among the positive experiences, some reported that families were bound together during the illness and characterized the time spent with the patient as quality time. Some FCs reported that they learned a lot and experienced the caregiving as meaningful, purposeful, and satisfying. FCs in some studies experienced caregiving as positive for their self-esteem 75. At the same time, others reported that the process of caregiving could be described as riding an emotional roller coaster. Struggling with one's own feelings was described as a huge challenge 58.

The burden of caregiving responsibilities

Several studies reported that caregivers of cancer patients are exposed to a considerable burden as a result of the many responsibilities they handle for long periods. Tasks related to direct and indirect care for the patient were most frequently mentioned, but other care responsibilities were also experienced as burdens. Care is often a difficult, disruptive, and time-consuming activity 76. FCs reported spending the most time in providing transportation, running errands, giving emotional support, monitoring symptoms, and performing extra household tasks 77–79. Personal tasks (e.g. feeding, washing the patient) were perceived as more difficult and burdensome than non-personal tasks (e.g. transportation). FCs reported problems with balancing the needs of other family members 59. The caregiver burden is based more on subjective experiences and the perceived availability of social support, rather than the actual amount of assistance provided. Studies have identified that FCs with more limited social networks are more likely to feel burdened. These results underscore the importance of a social network for FCs 80.

How do FCs describe their problems and the caregiving burden?

In order to understand and assist FCs, it is important to examine how FCs describe their problems and their caregiving burden. Therefore, we identified the words and expressions FCs used to describe their experiences to reflect the depth and diversity of their problems. Most of these words come from 15 studies 49, 58, 61, 62, 69, 73, 81–89 that employed methods in which the FCs were audio- or videotaped, and were the emphasis on how FCs described their experiences in their own words.

The actual words used by FCs were more descriptive than clinical in nature. The following examples illustrate this point: ‘Lie waiting for the next earthquake and never sleep’. ‘I did not get paid—worried about what to eat for the next year’, ‘from spouse to nurse’, ‘overwhelming sense of being alone’, ‘some information was not there unless we knew what question to ask’, ‘try to maintain a positive attitude’, ‘navigate a small boat through a storm with no prior experience’, ‘problem to balance caring while keeping life as normal as possible for the children’, and ‘feel trapped in care responsibilities’.

Thus, we know that FCs use a somewhat different terminology to express their problems and responsibilities than would clinicians. Realizing this difference should help clinicians better understand and communicate with FCs about problems and responsibilities. However, more research is needed on FCs words, expressions, thoughts, beliefs and perceptions, and their understanding of problems.


  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

This literature review, based on 192 articles published between 1990 and 2008, is to our knowledge the first comprehensive review that includes an entire range of problems as reported in the literature of FCs of cancer patients, including FCs' experiences and perspectives, and the language and terms they use to communicate their problems. Although a few earlier reviews exist 12–23, most of them focused only on selected problems or the burden imposed by caregiving responsibilities, or were limited to short follow-up periods. Although most of the problems located in our research were social and emotional, this review provides significant evidence that FCs of cancer patients experience a large number of complexes—social, emotional, and health-related problems—as well as significant burdens related to caregiving responsibilities assumed during and after a patient's treatment for cancer.

However, this review also revealed some knowledge gaps, and thus suggestions for further research. For example, few studies have compared specific problems and burdens associated with a patient's cancer diagnosis. There is also a paucity of information on the relationships between demographic characteristics (e.g. ethnicity, gender, family structure, socioeconomic status, and cultural heritage), and problems and burdens. FCs from different cultural, geographic, and socioeconomic backgrounds may experience problems and the caregiving burden differently, or may have different support structures. Despite the fact that much of what we know about FCs problems and burden comes from Caucasian samples, FCs in studies from different parts of the world have much in common with these caregiving experiences. Knowledge about any differences, however, would be important information for clinicians that could help them individualize support for FCs. Therefore, more studies are needed to explore differences in symptoms, problems, and perceptions of the caregiving experience in FCs from different cultural, ethnic, or socioeconomic backgrounds.

Very few studies have addressed how caregiver problems and responsibilities change during different stages in a patient's illness trajectory. It is likely that variations exist in symptoms, problems, and responsibilities depending on the severity of patient's illness. FCs problems may be predominantly psychological in the patient's early stage of treatment, but more psychosocial or physical in later stages. Problems may be acute or chronic. There is also little research about how other variables change during the course of the FC experience, such as employment, social support, role strain, anxiety, depression, and quality of care for the patient. That problem experience varies widely during different stages of the illness was found in adult cancer patients 58, 90. Therefore, it is highly likely that FCs experience similar variations as well. Thus, more longitudinal studies are needed to better understand how symptoms, problems, and the overall FC burden vary over time. More knowledge is needed to understand how deeply these problems and the caregiving burden interfere with FCs' lives, and how FCs could prioritize problems and responsibility alleviation.

Our review has some limitations, primarily related to the motivation for this review: we wanted to lay the groundwork for developing an Internet-based support system for FCs of cancer patients. Therefore, we focused our attention on identifying the breadth and depth of physical, social, and psychological health problems, and the burden related to caregiving responsibilities. In addition, we identified the language and concepts FCs use to communicate their problems and describe their burden, and how these are experienced from the FCs perspective. Our approach was that ‘anything goes’—if a problem was reported in the literature, it was a candidate for inclusion on our list of problems.

Therefore, we did not summarize the frequency of reported problems, nor did we assess the quality of research studies or the validity or reliability of instruments used to elicit symptoms. The focus was on summarizing knowledge on the types of problems, not summarize the state-of-art in FC research. This question would have required a different type of review. The main aim of this review was to capture the full breadth of self-reported problems, rather than weighting articles in regard to method used or impact factor. Hence, quantifying the frequency of self-reported problems was not done in this study. The most prevalent observations are listed, but there is no frequency-based cut-off point. However, this review provides an important basis for a better understanding of the complexity of health problems in FCs of cancer patients. This knowledge may contribute to improved communication between FCs and clinicians, and to better support systems for FCs.


  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

This work was funded partially by South-Eastern Norway Regional Health Authority and Section for Social Medicine, Rikshospitalet, Oslo University Hospital, Norway.


  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References